Velilla Paula A, Rugeles Maria T, Chougnet Claire A
Group Immunovirology, Biogenesis Corporation, University of Antioquia, Medellín, A.A. 1226 Colombia.
Clin Immunol. 2006 Dec;121(3):251-9. doi: 10.1016/j.clim.2006.08.010. Epub 2006 Sep 28.
Immaturity of the immune system has been suggested as an underlying factor for the high rate of morbidity and mortality from infections in newborns. Functional impairment of neonatal T cells is frequently quoted as the main underlying mechanism for such immaturity. However, recent studies suggest that neonatal antigen-presenting cells (APCs) also exhibit functional alterations, which could lead to secondary defects of adaptive T-cell responses. In this review, we summarize what is known on the functionality of APC at birth and during early childhood. Compared to adults, neonatal APCs display markers of immaturity and produce low levels of cytokines. Multiple factors could be involved in neonatal APC alteration, such as intrinsic immaturity, defective interaction between APCs and T cells and regulatory T-cell-mediated inhibition. Characterization of the relative contribution of each mechanism is clearly needed to better understand the functional capability of the neonatal immune system.
免疫系统不成熟被认为是新生儿感染发病率和死亡率高的一个潜在因素。新生儿T细胞的功能受损常被认为是这种不成熟的主要潜在机制。然而，最近的研究表明，新生儿抗原呈递细胞（APC）也表现出功能改变，这可能导致适应性T细胞反应的继发性缺陷。在这篇综述中，我们总结了关于出生时和幼儿期APC功能的已知情况。与成年人相比，新生儿APC表现出不成熟的标志物，并且产生低水平的细胞因子。多种因素可能参与新生儿APC的改变，如内在不成熟、APC与T细胞之间的相互作用缺陷以及调节性T细胞介导的抑制。显然需要明确每种机制的相对贡献，以便更好地理解新生儿免疫系统的功能能力。
